how much should i sand and with what grit, do i go to the gel coat to fix cracks or all the way to the fiberglass.



14.728 @ 92.14 (65 shot)

chances are that sanding to fiberglass will reveal pin holes and the bumper will need to be primed, most times if you leave the gel coat intact you can just scuff it and base and clear it. If the scratches or what ever you are fixing is deep and you go to fiberglass, just put a skim coat of icing on it, it should get rid of pin holes, but the bumper will need to be primed. If you have an actual crack, like the fiberglass is split, then you should go to fiberglass and sand the area with 40 grit and do the repair then sand the repair with 80 and 180